SPECIES DIVERSITY OF HIGHER PLANT OF QUERCUS LIAOTUNGENSIS FOREST IN QINLING MOUNTAIN AND THE LOESS PLATEAU Effects of slope position on soil microbial biomass of Quercus liaotungensis forest in Dongling Mountain The Characteristics of Stand Structure and Spatial Distribution of Quercus liaotungensis Forests in Liupan Mts. STUDY ON POPULATION DIAMETER STRUCTURES OF TREE AND SHRUB DOMINANT PLANTS IN QUERCUS LIAOTUNGENSIS FOREST IN DONGLING MOUNTAIN IN BEIJING QUANTIZING ANALYSIS ON DYNAMIC OF AGE-CLASS STRUCTURE OF ARBOR POPULATIONS IN QUERCUS LIAOTUNGENSIS FOREST The bio-cycle patterns of nutrient elements and stand biomass in forest communities in Hilly Loess Regions Photosynthetic Physiological and Ecological Characteristics of Betula platyphylla-Quercus liaotungensis Mixed Forests in Ziwuling Forest Area